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Lactobacillus casei LM -1 의 Bacteriophage 저항성 기작에 관한 연구
임광세(K . S . Lim),장영호(Y . H . Jang),백영진(Y . J . Baek),김현욱(H . U . Kim) 한국축산학회 1991 한국축산학회지 Vol.33 No.10
This study was carried out to elucidate the phage defense mechanism of Lactobacillus casei LM-1, the phage-resistant mutant of L. cased S-1, and to obtaine the basic knowledge for developing a better lactic starter bacteria resistant to the phages. The results obtained are summarized as follows ; 1. No differences were found in growth, acid production, and carbohydrate fermentation between L. casei S-1 and L. casei LM-1 in the MRS broth. and transmission electron microscopic studies of L. case; LM-1 revealed that cells were covered with the hairly capsular layer, that is presumed to cover up the phage receptor sites on the surface of the cells. 2. When the cells of L. casei S-1 were treated with mutanolysin, the adsorption rate of phage J-I and ø-I was decreased rapidly. In case of L. casei LM-l, the adsorption rate of phage J-1 and ø-1 was increased around 30 minutes after addition of mutanolysin and then decreased. 3. Based upon the knowledge obtained from enzymatie treatment; and electron micrographs of L. casei LM-I, it is safe to say that the phage-resistant harrier of L. case; LM-1 is the extension of the modified pep-tidoglycan layer of the normal cell wall. 4. Treatment of L. casei LM-1 with 3 kinds of enzymes (subtilisin. α-amylase, β-amylase) did not affect the low adsorption of phage J-I and ø-1 on the host cells. which tells the capsular layer of L. casei LM-1 was not hydrolyzed by these enzymes. 5. No plasmids of L. casei S-1 and L. easei LM-1 were found on agarose gel electrophoresis, which suggests that the gene responsible for the formation of capsular layer was possibly induced due to the chromosomal mutation.